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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Joakim Zhang <qiangqing.zhang@nxp.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 069/215] net: phy: realtek: add delay to fix RXC generation issue
Date:   Thu, 15 Jul 2021 20:37:21 +0200
Message-Id: <20210715182611.595460325@linuxfoundation.org>
In-Reply-To: <20210715182558.381078833@linuxfoundation.org>
References: <20210715182558.381078833@linuxfoundation.org>
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From: Joakim Zhang <qiangqing.zhang@nxp.com>

[ Upstream commit 6813cc8cfdaf401476e1a007cec8ae338cefa573 ]

PHY will delay about 11.5ms to generate RXC clock when switching from
power down to normal operation. Read/write registers would also cause RXC
become unstable and stop for a while during this process. Realtek engineer
suggests 15ms or more delay can workaround this issue.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/phy/realtek.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 575580d3ffe0..b4879306bb8a 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -246,6 +246,19 @@ static int rtl8211f_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+static int rtl821x_resume(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = genphy_resume(phydev);
+	if (ret < 0)
+		return ret;
+
+	msleep(20);
+
+	return 0;
+}
+
 static int rtl8211e_config_init(struct phy_device *phydev)
 {
 	int ret = 0, oldpage;
@@ -624,7 +637,7 @@ static struct phy_driver realtek_drvs[] = {
 		.ack_interrupt	= &rtl8211f_ack_interrupt,
 		.config_intr	= &rtl8211f_config_intr,
 		.suspend	= genphy_suspend,
-		.resume		= genphy_resume,
+		.resume		= rtl821x_resume,
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
 	}, {
-- 
2.30.2